Combined high and low pressure pumping apparatus



May 31, 1960 A. E. MCFARLAND ET AL 2,938,465

COMBINED HIGH AND LOW PRESSURE PUMPING APPARATUS Original F iled Aug.31, 1953 2 Sheets-Sheet 1 Ar fhur E. Me Far/arm /4/' f/e F. Ma Far/andINVENTORS Z IMVZW ATTORNEY May 31, 1960 A. E. MCFARLAND ET AL 2,938,465

COMBINED HIGH AND LOW PRESSURE PUMPING APPARATUS Original Filed Aug. 31,1953 2 Sheets-Sheet 2 Arf/w/ .5 Mc Far/and Arf/e F McFar/ana INVENTORJ'ATTORNEY COMBINED HIGH AND LOW PRESSURE PUMPING APPARATUS Arthur E.McFarland, 2284 Collier St., and Artie F. Mc- Farland, 7208 BrownwoodSt., both of Houston, Tex.

Original application Aug. 31, 1953, Ser. No. 377,274,

now Patent No. 2,812,771, dated Nov. 12, 1957. Divided and thisapplication Apr. 22, 1957, Ser. No.

3 Claims. (Cl. 103-37) This invention relates to combined high and lowpressure pumping apparatus, and more particularly to equipment forpumping liquids and control mechanism therefor for use in the testing ofapparatus or devices whic are to be subjected to fluid pressures.

This application is a division of a prior application of the sameapplicants filed August 31, 1953 under Serial Number 377,274 whichissued on November 12, 1957 as Patent No. 2,812,771.

The invention finds particular application in connection with thetesting of pipe lines and containers such as tanks, which may besubjected to high fluid pressures in use, and in which it is desirableto determine the pressures which such equipment is capable ofwithstanding, or the pressures which may safely be applied thereto.

In the testing of equipment of the kind referred to by the use ofhydraulic fluid it is necessary to first substantially fill theapparatus or device with the fluid before pressure can be applied to thesame and in the case of equipment of large capacity much time may beexpended in merely filling the same prior to the actual testing period.Pumping equipment of large capacity may be used in substantially ornearly filling the apparatus or device to be tested, but when the samehas been nearly filled, only a small additional amount of fluid isrequired to complete the fillin operation and raise the pressure of thefluid to the desired degree, for which such large capacity pumpingequipment is unsuitable, so that additional pumping equipment of smallcapacity capable of developing high fluid pressures is necessary, andmeans must be provided for shutting oil the large capacity equipment andconnecting in the high pressure equipment at .the proper time in orderto complete the testing operation.

The present invention has for an important object the provision ofcombined high and low pressure pumping equipment for use in hydraulictesting apparatus whereby .theiapparatus or device to be tested may berapidly filled or nearly filled with hydraulic fluid and a small amountof fluid then applied thereto to complete the filling operation andraise the pressure of the fluid in the apparatus or device to thedesired testing pressure.

Another object of the invention is to provide high and low pressurepumping equipment including pumping means of relatively large capacityand other pumping means of relatively small capacity and capable ofdelivering-fluid at a relatively high pressure, and mechanism which isoperable automatically when the pressure of fluid in the fluid deliveryline of the equipment reaches a predetermined limit to shut off theflow-of fluid from the ,large capacity pumping means through thedelivery line and cause the small capacity pumping means to deliverfluid at high pressure to the delivery line.

A further obj ct of the invention is the provision of high and lowpressure pumping equipment embodying double acting pump mechanism andcontrol means therefor whereby a large volume of hydraulic fluid may besupplied to any desired apparatus or device to be tested hydraulicallyin order to quickly fill the same, and thereafter a relatively smalladditional volume of fluid may be supplied at high pressure to increasethe pressure of fluid in the apparatus or device to be tested at thedesired testing pressure.

Another object of the invention is to provide high and low pressurefluid pumping mechanism and valve means operable upon a predeterminedincrease in the pressure of fluid delivered from such mechanism forcausing-the outflow of fluid from the low pressure mechanism to bebypassed to the inflow thereof whereby the low pressure mechanism isrendered inactive, and for causing the high pressure mechanism todeliver fluid at high pressure.

A still further object of the invention is the provision of an improveddouble acting high and low pressure fluid pumping mechanism and animproved pressure fluid motor for operating the same.

Other important objects and advantages of the invention will best beunderstood from the following detailed description, constituting aspecification of the same, when considered in conjunction with theannexed drawings, wherein- Figure 1 is a diagrammatic view of theinvention, showing the arrangement of the various elements of thehydraulic testing equipment;

Figure 2 is a central, longitudinal, cross-sectional view on an enlargedscale of the valve which controls the ,delivery of high and low pressurefluid to the apparatus or device to be tested;

Figure 3 is a cross-sectional view, on an enlarged scale, taken alongthe line 3--3 of Figure 4, looking in the direction indicated by thearrows and showing the construe.- tion of the valve of'the pressurefluid operated motor by which the pumping mechanism is operated, and

Figure 4 is a side View, partly broken away and partly in cross-section,showing the details of construction of the high and low pressure pumpingmechanism and the pressure fluid operated motor by which the same isoperated.

Referring now to the drawings in greater detail, the inventioncomprises, briefly stated, a pressure fluid operated motor 10, of thereciprocating type, connected in driving relation to identical high andlow pressure fluid pumps 12, 12, in a manner to operate both of saidpumps upon one complete cycle of the operation of the motor, each ofsaid pumps having suitable valve mechanism, indicated generally at '14,14, and being connected in communication with a fluid supply line 16,and a fluid delivery line 18, and a bypass valve '20, and a pressurecontrol valve 22, whereby the flow of low and high pressure fluiddelivered to the apparatus or .device to be tested is automaticallycontrolled. i q

The pressure fluid operated ,motor 10 has a cylinder 24,

in which longitudinally spaced pistons 26 and 28 are movably disposed atthe opposite ends of a connecting shaft 30. At its opposite endsthecylinder 24 is provided with suitable cylinder heads 32, 32, throughwhich pump rods 34, 34 extend .through control openings in the cylinderheads, suitable packing, such as that indicated at 36, 36, beingprovided on the cylinder heads surrounding the pump rods, to preventleakage of pressurefluid from the interior of the cylinder. The .pumprods 34, 34 are @ttached at their inner ends .to the opposite ends ofthe shaft 30, to reciprocate therewith .upon operation of the pressurefluid motor, and each of these pump rodsfcafries at its outer end a lowpressure pump piston 38, which works in a low pressure cylinder v4t),connected to the respective cylinder head 32.

Each of the pump rods 34 has a counterbore 42, which opens outwardly atthe outer end of the rod, and forms a high pressure cylinder within theouter end of which a tubular high pressure piston 44 extends, throughfasuitable packing gland 46, whereby the high pressure cylinder mayreciprocate back and forth on the high leads to the atmosphere.

pressure piston during the pumping operation. Each high pressure piston44, is attached at its outer end to an outer cylinder head 48, on therespective low pressure cylinder 40, and within which there is a highpressure chamber 50, within the interior of which the high pressurepiston communicates.

The valve mechanism by which the intake and ex- ;haust of pressure fluidto and from the pressure fluid operated motor is controlled is enclosedin a housing 52 attached to the cylinder 24, and which has an internalcylindrical valve chamber 54 in which a double piston valve havingspaced pistons 56 and 58 connected by a piston rod 60 is movablypositioned. The valve housing 52 has an inlet opening to which an intakepipe 62 is connected which leads to any convenient source of operatedpressure fluid. The housing 52 also has ports in communication with thechamber 54 and with passageways 64 and 66 leading to the opposite endsof the cylinder 24. An exhaust passageway 68 is also provided whichcommunicates with the chamber 54 at a location between the passageways64 and 66 and which The double piston valve has an exhaust valve body 70carried on the piston rod 60 and which has an external recess 72 adaptedto be brought into communication with the passageways 66 and 68 in oneposition of the valve to permit fluid to be exhausted to the atmospherefrom one end of the cylinder 24, and which communicates with thepassageways 64 and 68 in another position of the valve to allow fluid tobe exhausted from the other end of the cylinder 24.

The pistons 56 and 58 are positioned somewhat beyond the opposite endsof the exhaust valve 'body70, so that when the exhaust valve is in apositionto permit exhaust of fluid through passageways 66 and 68 fromone end of the cylinder, fluid from the intake pipe 62 may flow throughpassageway 64 to the opposite end of the cylinder 24, as seen in Figure4. Similarly, when the exhaust valve 70 moves to a position to permitthe exhaust of fluid through the passageways 64 and 68, the intake pipewill be in communication with the passageway 66.

Surrounding the shaft 30 between the pistons 26 and 28 in the cylinder24 there is a spool valve 73 having pistons 74 and 76 at its oppositeends providing an annular recess 78, and a passageway 80 is formed inthe housing 52, as best seen in dotted lines in Figure 3, whichcommunicates with a passageway 82 in the cylinder 24 leading into therecess 78. The passageway 80 leads into the chamber 54 of the housing 52and the exhaust valve 70 is cut away as indicated at 84, so that thepassageway 80 is always in communication with the intake pipe 62. Thepassageway 80 is also positioned to be in communication with the recess78 in all positions of the spool valve 73.

I From the interior of the cylinder 24 passageways 86 and 88 lead to theopposite ends of the chamber 54.

The passageways 86 and 88 are positioned so that the passageway 86 isopen and passageway 86 will be closed by piston 26 when the passagewayis open.

' In the operation of the pressure fluid motor-the parts will be in therelative positions seen in Figure 4 when the pistons 26 and 28 are atone extreme position of their movement in the cylinder 10. In thisposition of the motor the piston 28 has just engaged the spool valve 73to move this valve to cut ofl the passageway 88 and open the passageway86 to the inflow of fluid from the intake pipe 62 through passageways 80and 82 to recess 78 and thence to the chamber 54 to act on piston 56 tomove the exhaust valve body 70 to the position shown. Fluid from intakepipe 62 may now enter the cylinder 24'through passageway 64 to act onpiston 26 to move the same toward the opposite end of the cylinder whilefluid may exhaust from said opposite end through passageway 66, recess72 and passageway 68. When piston 26 engages spool valve 73 it will movethe spool valve with it toward the opposite end of cylinder 24 to closepassageway 86 and open passageway 88, whereupon pressure fluid fromintake pipe 62 will enter chamber 54 to act on piston 58 to move theexhaust valve 70 to establish communication between passageways 64 and68 and permit fluid from the intake pipe to again enter throughpassageway 66 to act on piston 28 to move the same back to the positionshown in Figure 4.

The motor may be operated in the manner described above to operate thepump pistons 38, 38 and 44, 44 at substantially constant speed.

Connected in communication with each of the low pressure pump cylinders40 there is an inlet check valve housing 90, with which the hydraulicfluid supply pipe 16 is alsoconnected, and each valve housing has aninternal valve seat and a ball valve 92 which engages the seat to closethe valve against outflow of fluid from the cylinder 40. An outlet checkvalve housing 94 is similarly connected in communication with theinterior of each low pressure pump cylinder 40 and with an outlet pipe96, and has an internal valve seat for an outwardly opening ball checkvalve 98. It will be apparent that with the valve arrangement asdescribed movement of the pistons 38 in one direction in the cylinders40 will cause hydraulic fluid to be drawn into one cylinder while beingdischarged from the other cylinder, and that this action will bereversed when the pistons move in the other direction, thus securingapumping stroke in either direction of movement of the motor pistons.

Similar inlet and outlet check valves and 102, respectively, areprovided connected in communication with each of the high pressure pumpchambers 50, an inlet passageway 104, being provided in each of theheads 48 leading from the interior of the corresponding cylinder 40' tothe inlet valve. The outlet valves 102 are connected in communicationwith an outlet pipe 106. By this arrangement hydraulic fluid will bedrawn into one of the high pressure pump chambers 50 and discharged fromthe other high pressure chamber.

The structure of the pressure delivery control valve mechanism 22 isshown in detail in Figure 2, wherein the valve casing is indicated at108 having a low pressure inlet 110 adapted to be connected incommunication with the low pressure outlet pipe 96 through a branch pipe112, shown in Figure 4, and a high pressure inlet 1-14 for connection incommunication with the high pressure outlet pipe 106 through branch pipe116. The valve casing 108 also has an outlet 118 formed in the housingand closure 120 for connection to the hydraulic fluid delivery pipe 18leading to the apparatus or device to be tested. The pressure deliverycontrol valve has an internal chamber 122, into which an internal sleeve124 extends, which sleeve is attached at its outer end to the interiorof the casing within the inlet 110 and has at its inner end a taperedvalve seat 126 spaced inwardly of the closure 12!). A tubular piston 128is movably disposed in the casing extending between the sleeve 124 andthe interior of the casing. A coil spring 130 is positioned around thesleeve 124 and hearing at one end against the piston 128 and at theother end against the casing at one end of the chamber 122 to yieldinglyurge the piston toward the closure 120. The piston 128 is provided withan internal web 132, to which a tapered valve element 134 is attached bysuitable means, such as a screw 136 extending through a central openingin the web, in position to seat on the seat 126 when the piston 128moves toward the inlet 110. The piston 128 also has openings 138 and 140disposed on opposite sides of the web 132 through which low pressurefluid may flow from the inlet 110 through the sleeve 128 and out of theoutlet 118 when the valve 134 is in open position. High pressure fluidmay also flow from the inlet 114 through the openings 140 to the outlet118. The valve casing 108 has an opening 142 through which air may passinto and out of the portion of the chamber 122 in which the spring 130is located.

The equipment also includes the by-pass valve 20, which comprises avalve casing 144 having an internal valve seat 146 and a valve 148 whichis urged into closing contact with the seat by a coil spring 150. Thecasing 144 has an inlet 152 connected in communication with the outletpipe 96 and an outlet 154 connected in communication with the supplypipe 16, whereby fluid may pass from the outlet pipe 96 back to thesupply pipe 16 when the valve 148 is open. The by-pass valve mechanismalso includes a cylinder 156 connected at one end in communication withhigh pressure outlet pipe 106 and within which a plunger 158 is movable,which plunger extends beyond the opposite end of the cylinder and intothe valve casing 144 to engage the valve 148 and move the valve to openposition against the pressure of the spring 150. The spring 150 may beof suflicient strength to maintain the valve 148 closed during thepumping of hydraulic fluid from the low pressure cylinders 40, and untilthe pressure in the high pressure outlet pipe 106 exceeds apredetermined limit, whereupon the plunger 158 will be actuated to openthe valve 148 and permit the low pressure fluid to pass from the lowpressure outlet pipe 96 back to the supply pipe 16, thus inactivatingthe low pressure pumping mechanism.

In the operation of the equipment, as used, for example, in connectionwith the hydraulic testing of pressure vessels, or the like, the fluidmotor is operated by the application of pressure fluid thereto throughthe intake 62, to actuate the low pressure pistons 38 and high pressurepistons 44. Hydraulic fluid is thus drawn into the low pressurecylinders 40 and pumped therefrom into the low pressure outlet pipe 96from whence it flows through the pipe 112 to the pressure deliverycontrol valve 22 and through pipe 18 to the apparatus or device to betested. During the pumping of the fluid at low pressure the valve 134will be open and fluid may also be pumped from the high pressure chamber50 through high pressure outlet pipe 106 to the inlet 114 of valvemechanism 22 from whence it flows to the apparatus or device beingtested.

When the apparatus or device being tested has been filled or nearlyfilled with hydraulic fluid the pressure in the delivery line will besuddenly increased, so that the pressure of fluid in the low pressureoutlet pipe 96 will be insufiicient to cause further flow of fluidthrough the pressure delivery control valve, whereupon high pressurefluid from the high pressure outlet pipe will enter the inlet 114 tofurther increase the pressure in the delivery pipe 18 causing the valve134 to close against the pressure of the spring 130 on the piston 128.The high pressure of fluid in the outlet pipe 106 will also cause theplunger 158 to open the by-pass valve 148 whereby fluid from the outletpipe 96 may return to supply pipe 16, thus permitting the piston 38 tomove without resistance during the high pressure pumping operation.

It will thus be seen that the invention constructed and operated in themanner described above provides combined high and low pressure pumpingmechanism by which the apparatus or device to be tested may be quicklyfilled with hydraulic testing fluid and thereafter subjected to a hightesting pressure.

While the invention has been disclosed herein in connection with acertain specific embodiment of the same, it will be understood that thisis intended by way of illustration only, and that numerous modificationscan be made in the construction and arrangement of the various partswithout departing from the spirit of the invention or the scope of theappended claims.

Having thus clearly shown and described the invention, what is claimedas new and desired to secure by Letters Patent is:

1. In a combined high and low pressure pump a low pressure cylinder, acylinder head on one end of said cylinder, a high pressure chamber insaid head, said cylinder having an inlet in communication with theexterior of the cylinder and a passageway in said head leading from theinterior of the cylinder into said chamber, means in said passageway forpreventing the backflow of fluid from said chamber into said cylinderthrough said passageway, a piston movably disposed in said cylinder forreciprocation therein, a piston rod connected to said piston and havinga longitudinal bore closed at one end and whose other end terminates insaid cylinder, a stationary tubular element in the cylinder andextending at one end into said bore and whose other end is inc0mmunication with said chamber.

2. In a combined high and low pressure pump low pressure cylinders, acylinder head on one end of each cylinder, a high pressure chamber ineach head, each of said cylinders having an inlet from the exterior ofthe cylinder and a passageway in the head of each cylinder leading fromthe interior of the cylinder into the chamber in the head, means in saidpassageways for preventing the backflow of fluid from the chambers intothe cylinders, a piston movably disposed in each cylinder forreciprocation therein, a piston rod connected to each piston formovement therewith and having a longitudinal bore closed at one end andwhose other end terminates in the cylinder, a stationary tubular elementin each cylinder and extending at one end into the bore of the pistonrod of the cylinder and whose other end is in communication with thechamber of the head of the cylinder, and means for alternatelyintroducing fluid under pressure into each end of the cylinder whileexhausting such fluid from the other end thereof to cause the piston toreciprocate.

3. In a combined high and low pressure pump low pressure cylinders, acylinder head on one end of each cylinder, a high pressure chamber ineach head, each of said cylinders having an inlet and an outlet, apassageway in the head of each cylinder leading from the interior of thecylinder into the chamber of the head, means in the passageways forpreventing backflow from the chambers into the cylinders, a pistonmovably disposed in each cylinder for reciprocation therein, a pistonrod connected to each piston and having a bore closed at one end andwhose other end terminates in the cylinder, a stationary tubular elementin each cylinder and extending at one end into the piston rod thereinand whose other end is in communication with the chamber in the head ofthe cylinder, means for alternately introducing fluid under pressureinto each end of the cylinder while exhausting such fluid from the otherend thereof to cause said piston and piston rods to reciprocate andmeans in said outlets for closing the one of said outlets upon movementof the piston rods in one direction and for closing the other of saidoutlets upon movement of the piston rods in the other direction.

References Cited in the file of this patent UNITED STATES PATENTS833,457 Hammond Oct. 16, 1906 867,932 Weeks Oct. 8, 1907 1,521,461Madden Dec. 30, 1924 1,551,480 Gruman Aug. 25, 1925 2,080,809 Dinkel May18, 1937 2,411,438 Lane Nov. 19, 1946 2,633,082 McFarland Mar. 31, 19532,820,415 Born Jan. 21, 1958 FOREIGN PATENTS 805,957 Germany June 18,1951

